In particular because of the development in the performance levels of digital memories and of audio data compression systems, there currently exist a large number of digital portable personal stereos.
In general, such a portable personal stereo includes a high-capacity internal digital memory connected to a communications interface by means of which it is possible to record audio content in the digital memory from external equipment such as a computer.
Such a portable personal stereo also includes an electronic circuit for write and read accessing a memory, and a control interface that can be of various degrees of sophistication. Said interface is used for controlling operation of the portable personal stereo, and in particular for controlling write and read accessing of the digital memory.
That applies, for example, to the digital portable personal stereo described in Patent Document US 2003/0016940.
Because of their complexity and of the need to interconnect them with other equipment, such portable personal stereos require advanced electronic circuits; that poses problems in terms of cost, of consumption, and of sturdiness, in particular when the size of the portable personal stereos is small. Similarly, the communications interfaces are elements that are costly and fragile.